1. Field of the Invention
The present invention generally relates to electrostatic chucks and more particularly to an improved electrostatic chuck that includes height adjustment mechanisms to compensate for foreign matter particles and to improve flatness of the item being clamped.
2. Description of the Related Art
There are many situations when it is important to hold a device, such as a layer of material, a laminated structure, reflective mask, optical mask, etc. in an extremely flat manner. For example, Extreme Ultraviolet Lithography (EUVL) is a promising technology for the next generation lithography. Image placement specifications for this technology are very tight and in order to meet these specifications, masks must be as close to perfectly flat as possible in the stepper as well as in the write and inspection tools used in the manufacturing of these masks. Electrostatic chucks (ESC) can be used to pull the EUVL mask flat at the necessary processing steps that require a perfectly flat mask, such as the stepper, write tool, or inspection tool.